The people of the Mission Safe Zone have a problem. Nine years have passed since the dead rose and civilisation crumbled. The Mission Safe Zone, established in the first year of the outbreak, has managed to keep thousands of living humans safe from the undead hordes. But now people are going missing, vanishing without trace, and Sheriff Jim Reilly suspects a new threat exists inside the Wall that surrounds the Safe Zone. Reilly believes that a serial killer lives among the survivors.

For salvagers Robyn Cartwright and Amanda Martin, a serial killer is the least they have to worry about. Something is going on with the undead outside the Wall, something that could have deadly repercussions for the Safe Zone, and every living thing within it.